• Biomolecules & Therapeutics
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• v.5 no.1
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• pp.36-42
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• 1997

To investigate effects of ginseng total saponin (GTS) on the ethylcholine aziridnium ion (AF64A) -induced glutamatergic nervous system, rats were pretreated with the infusion of AF64A (3 nmole) into lateral ventricle and were posttreated with 50 mg/kg of GTS, i.p., for 1 week. Twenty four hours after the last administration, rats were sacrificed and the levels of glutamate and taurine, [$^3$H]dizocilpine ([$^3$H]MK801) binding sites and glutamine synthetase activity were assessed in striatum, hippocampus and frontal cortex. The levels of striatal glutamate after GTS treatment in rats were decreased. And the levels of glutamate were decreased in striatum and frontal cortex and increased in hippocampus by the infusion of AF64A. However, the AF64A-induced changes of glutamate were returned to the control level by the administration of GTS in striatum, frontal cortex and hippocampus. After the infusion of AF64A, the level of taurine was decreased in striatum and increased in hippocampus. GTS administrations in the AF64A-treated rats restored to the control level of taurine in the decreased striatal level of taurine, but not in the elevated level of hippocampal taurine. The specific [$^3$H]MK801 binding sites in hippocampus was significantly decreased but not in striatum and frontal cortex after the administration of AF64A. Although GTS itself did not affect the specific [$^3$H]MK801 binding sites, GTS administrations in the AF64A-treated rats did decrease the binding sites of (\`H)Mk801 in all examined regions. The activities of striatal glutamine synthetase were decreased after GTS treatment. The activities of striatal glutamine synthetase (GS) were decreased in AF64A-treated groups. However, the decreased striatal GS activities by AF64A were returned to the control level by GTS treatment. Furthermore, GTS administrations in the AF64A-treated rats increased the hippocampal GS activities. The results indicatethat GTS may adjust the levels of glutamate and taurine constantly and may induce increase in AF64A-induced decrease of GS activity. Thus, it suggests that GTS may antagonize changes in central glutamatergic nervous system induced by AF64A. Also it suggests that the actions of GTS may differently affect in the disease state.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.28-28
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• 2015

Clubroot disease caused by Plasmodiophora brassicae induces severe losses of cruciferous vegetables worldwide. To control clubroot of Chinese cabbage, many CR (clubroot resistance) F1 hybrid cultivars have been bred and released in Korea, China and Japan. In this study, we determined the race of P. brassicae 12 field isolates, which collected from 10 regions in Korea, using Williams' differential varieties including two cabbage ('Jersey Queen', 'Badger Shipper') and two rutabaga ('Laurentian', 'Whilhelmsburger'). By Williams' differential varieties, 12 clubroot pathogens were assigned into one (GN2), two (HS and YC), two (HN1 and HN2), three (DJ, KS and SS) and four (GS, GN1, JS and PC) isolates for races 1, 2, 4, 5 and 9, respectively. In addition, the degree of resistance of 45 CR cultivars that were from Korea, China and Japan was tested with the 12 isolates. The 45 CR cultivars of Chinese cabbage were differentiated into three genotypes according to their resistance responses. Even though the 12 P. brassicae isolates were same race by Williams' differential varieties, three CR genotypes showed different resistance response to the isolates. These results indicate that races of P. brassicae by Williams' differentials were not related with resistance of CR cultivars, and three CR genotypes represented qualitative resistance to the P. brassicae isolates. CR genotype I including 'CR-Cheongrok' showed resistance to GN1, GN2, JS, GS, HS, DJ and KS isolates and susceptibility to YC, PC, HN1, HN2 and SS isolates. And CR genotype II such as 'Hangkunjongbyungdaebaekchae' was resistant to GN1, GN2, JS, GS, HS, YC, PC and HN1 and susceptible to DJ, KS, SS and HN2. CR genotype III including 'Chunhajangkun' and 'Akimeki' represented resistance to 10 isolates except for SS and HN2 isolates. Based on these results, we selected 'CR-Cheongrok', 'Hangkunjongbyungdaebaekchae', and 'Chunhajangkun' as a representative cultivar of three CR genotypes and 'Norangkimjang' as a susceptible cultivar. Furthermore, we investigated the resistance of 15 lines of Chinese cabbage, which were provided by seed companies, to 11 isolates except for HN1 of P. brassicae. The results showed that three lines were susceptible to all the tested isolates, whereas five, four, and three lines represented the similar responses corresponding to the CR genotypes I, II, and III, respectively; there is no line of Chinese cabbage showing different resistance patterns compared to three CR genotypes. In particular, line 'SS001' showing resistance responses of CR genotype II was a parent of 'Saerona' that have been commercialized as a CR $F_1$ cultivar of Chinese cabbage. Together, we divided 12 isolates of P. brassicae into 4 races, designated by wild type, mutant type 1, mutant type 2, and mutant type 3. Wild type including GN1, GN2, JS, GS, and HS isolates of P. brassicae was not able to infect all the cultivars of three CR genotypes, whereas, mutant type 3 such as SS and HN2 isolates developed severe clubroot disease on all the CR genotype cultivars. To mutant type 1 including DJ and KS isolates, CR genotypes I, II and III were resistant, susceptible and resistant, respectively. In contrast, to mutant type 2 including YC, PS, and HN1 isolates, CR genotypes I, II and III showed susceptibility, resistance and resistance, respectively. Taken together, our results provide the extended knowledge of classification of P. brassicae races, which is useful information for the breeding of resistant crops, with a suggestion that 'Norangkimjang', 'CR-Cheongrok', 'Saerona' and 'Chunhajangkun' cultivars of Chinese cabbage could be used as new race differentials of P. brassicae for clubroot disease assay.

• Journal of Environmental Science International
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• v.1 no.1
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• pp.51-59
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• 1992

Two comparative poplar clones (I-214: Populus euramerinm, Peace: P koreana x p. trihocarpa) were exposed to two $CO_2$ concentrations (350 or 2, 000 ${\mu}L L^{-1} CO_2$) for 21 days. When both poplar clones were compared at growth conditions, the net photosynthetic rate ($P_N$) in $CO_2$-enriched ($2, 000{\mu}L L^{-1} CO_2 = C_{2, 000}$) plants become about 50-60% higher than that of 350 ${\mu}L L^{-1} CO_2 (=C_{350}$ Plants on 7 days treatment. But the enhancement of PN by high $CO_2$ was not maintained throughout all the experimental period. At 21 days, there was no difference of photosynthetic rates between $C_{350}$ and $C_{2000}$ plants. In contrast with photosynthesis, the response of leaf conductance to the elevated $CO_2$ concentration was very different between I-214 and Peace. During all experimental period, leaf conductance ($g_{s}$) of $C_{2000}$ plants is 50% lower than that of the $C_{350}$ plants for I-214, while there is no difference of gs between the plants of $C_{350}$ and $C_{2, 000}$ for Peace. The results of gs in Peace indicate that decreased photosynthetic rate after 21 days in $C_{2, 000}$ Plants for two poplar clones is possibly due to non-stomatal factors. To investigate the non-stomatal factors, starch accumulation and ribulose-1, 6-bisphosphate carboxylase (RuBPCase) were measured. We found significant accumulation of starch in two poplar clones exposed to high $CO_2$, especially starch of I-214 in $C_{2, 000}$ become 3.5 times higher than in $C_{350}$ plants at 21 days. This suggests that high proportion of photosynthates was directed into starch. After 21 days, the activity of ribulose-1, 6-bisphosphate carboxylase of $C_{2, 000}$ plants become decreased in 40-50% compared with that of the $C_{350}$ plants. Two poplar clones show the same trend to RuBPCase declines under high $CO_2$ concentration, although the decline is more significant for I-214. The results reported here suggest that starch accumulation and decreased RuBPCase activity in $C_{2, 000}$ plants can be partly ascribed to the loss of photosynthetic efficiency of high $CO_2$-grown poplar plants.

• Korean Journal of Plant Resources
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• v.17 no.3
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• pp.227-238
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• 2004

Rhododendron micranthum is an endangered species in Korea. In order to develop the strategy of gene diversity conservation, estimation of the amount of genetic diversity, the genetic variation and relationship in the native populations of Rh. micranthum was performed on the basis of AFLP and RAPD analysis. Analysis of 56 accessions derived from 6 populations of Rh. micranthum with four AFLP primer combinations and ten RAPD primers detected a total of 33 polymorphic AFLP fragments and 15 polymorphic RAPD fragments, respectively. By UPGMA cluster analysis with molecular markers, the 56 accessions were grouped into three major clusters at 73.3% genetic similarity; group I consists of most accessions of populations I, II, IV, V and Ⅵ, group II consists of 7 accessions of population III, and group III consists of only two accessions of population IV. The geographic locations of the most accessions derived from six populations were not related to their position in the UPGMA cluster analysis, except for several accessions of populations III and IV. The genetic similarity of among six populations measured by AFLP and RAPD markers ranged from 0.66 to 0.99. Among them, population Ⅵ showed the highest GS with means of 0.87, while population I showed the lowest GS with means of 0.78. This result will be useful for designing the strategy of conservation in the native populations of Rh. micranthum.

• Analytical Science and Technology
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• v.19 no.3
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• pp.194-202
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• 2006

In this work, extraction and purification of the possible whitening agents from the Chinese plants; Chrysanthemum morifolium Ramat (xizang cai ju hua), Rhodiola sachalinensis, and Terminalia chebula Retzius have been described. The chopped leaves of Chrysanthemum morifolium Ramat and Terminalia chebula Retzius were added to water and ethyl ether, respectively. Components were separated on a GS310 column ($21.5{\times}500mm$ i.d., $10-15{\mu}m$) and concentrated into four or three portions. The chopped leaves of Rhodiola salientness were added to methanol and separated and concentrated on a column ($C_{18}$ column, $3.9^{\circ}$�F8;300 mm i.d., $15{\mu}m$) into two parts. The whitening effects of extracts were examined by in-vitro melanin production assay, in melana and B16 cells at a concentration of $10{\mu}g/ml$. The ethyl acetate layer of Chrysanthemum morifolium Ramat showed 92% melanin inhibitory at $200{\mu}g/ml$, the extract of Rhodiola sachalinensis showed a whitening effect of about 60% melanin inhibitory, which was more efficient than the whitening effect of arbutin (45.6%). The methanol extract of Terminalia chebula Retzius inhibited melanin expression by 90% at $100{\mu}g/ml$; however, it was toxic to B16 melanoma cells.

• Korean Institute of Interior Design Journal
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• v.24 no.3
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• pp.104-112
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• 2015

This study purposes drawing changing tendency of apartment kitchen areas and character of that by figuring out type, form and per period cause of change of brand apartment kitchen areas. I adopted subject of study as the six leading construction companies considering the apartment rankings of brand and subcontract from 2001 to 2015 when brand apartment was activated(Samsung C&T corporation Raemian, Daelim Industrial Co., Ltd E-pyeonhansesang, Daewoo E&C Prugio, GS E&C XI, Posco E&C The sharp, Hyundai E&C Hillstate) and analyzed kitchen plane of $84m^2{\sim}102m^2$ housing units which were in great demand from apartment housing market. Also, I drew changing trends of kitchen areas by conducting a model house field survey. Through this study result, I will expect the utility of baseline data which is necessary for space development by figuring out kitchen culture, flows and cause of change.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.213-219
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• 2004

In this paper, a LNA(Low Noise Amplifier) has been developed, which is operating at L-band i.e., 1452∼1492 MHz for satellite DAB(Digital Audio Brcadcasting) receiver. The LNA is designed to improve input and output reflection coefficient and VSWR(Voltage Standing Wave Ratio) by balanced amplifier. The LNA consists of low noise amplification stage and gain amplification stage, which make a using of GaAs FET ATF-10136 and VNA-25 respectively, and is fabricated by hybrid method. To supply most suitable voltage and current, active bias circuit is designed Active biasing offers the advantage that variations in $V_P$ and $I_{DSS}$ will not necessitate a change in either the source or drain resistor value for a given bias condition. The active bias network automatically sets $V_{gs}$ for the desired drain voltage and drain current. The LNA is fabricated on FR-4 substrate with RF circuit and bias circuit, and integrated in aluminum housing. As a reults, the characteristics of the LNA implemented more than 32 dB in gain. 0.2 dB in gain flatness. lower than 0.95 dB in noise figure, 1.28 and 1.43 each input and output VSWR, and -13 dBm in $P_{1dB}$.

• Journal of IKEEE
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• v.11 no.4
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• pp.272-278
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• 2007

In this paper, we report on the 2D (two-dimensional) simulation result of the DC (direct current) electrical and thermal characteristics of AlGaN/GaN HEMTs (high electron mobility transistors) grown on Si substrate, in comparison with those grown on sapphire and SiC (silicon carbide) substrate, respectively. In general, the electrical properties of HEMT are affected by electron mobility and thermal conductivity, which depend on substrate material. For this reason, the substrates of GaN-based HEMT have been widely studied today. The simulation results are compared and studied by applying general Drift-Diffusion and thermal model altering temperature as 300, 400 and 500 K, respectively. With setting T=300 K and $V_{GS}$=1 V, the $I_{D,max}$ (drain saturation current) were 189 mA/mm for sapphire, 293 mA/mm for SiC, and 258 mA/mm for Si, respectively. In addition, $G_{m,max}$ (maximum transfer conductance) of sapphire, SiC, Si was 38, 50, 31 mS/mm, respectively, at T=500 K.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.3
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• pp.196-208
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• 2007

An analytical model is proposed for an optically controlled Metal Semiconductor Field Effect Transistor (MESFET), known as Optical Field Effect Transistor (OPFET) considering the diffusion fabrication process. The electrical parameters such as threshold voltage, drain-source current, gate capacitances and switching response have been determined for the dark and various illuminated conditions. The Photovoltaic effect due to photogenerated carriers under illumination is shown to modulate the channel cross-section, which in turn significantly changes the threshold voltage, drainsource current, the gate capacitances and the device switching speed. The threshold voltage $V_T$ is reduced under optical illumination condition, which leads the device to change the device property from enhancement mode to depletion mode depending on photon impurity flux density. The resulting I-V characteristics show that the drain-source current IDS for different gate-source voltage $V_{gs}$ is significantly increased with optical illumination for photon flux densities of ${\Phi}=10^{15}\;and\;10^{17}/cm^2s$ compared to the dark condition. Further more, the drain-source current as a function of drain-source voltage $V_{DS}$ is evaluated to find the I-V characteristics for various pinch-off voltages $V_P$ for optimization of impurity flux density $Q_{Diff}$ by diffusion process. The resulting I-V characteristics also show that the diffusion process introduces less process-induced damage compared to ion implantation, which suffers from current reduction due to a large number of defects introduced by the ion implantation process. Further the results show significant increase in gate-source capacitance $C_{gs}$ and gate-drain capacitance $C_{gd}$ for optical illuminations, where the photo-induced voltage has a significant role on gate capacitances. The switching time ${\tau}$ of the OPFET device is computed for dark and illumination conditions. The switching time ${\tau}$ is greatly reduced by optical illumination and is also a function of device active layer thickness and corresponding impurity flux density $Q_{Diff}$. Thus it is shown that the diffusion process shows great potential for improvement of optoelectronic devices in quantum efficiency and other performance areas.

• Journal of the Korean Geosynthetics Society
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• v.5 no.1
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• pp.15-23
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• 2006

Sand Compaction Pile and Stone Column method have been used in widely during several decades as a technique to reinforce soft soils and increasing ultimate bearing capacity, accelerate consolidation settlement of the foundation ground. Stone column method, making a compaction pile using crushed stone, is a soft ground improvement method. However, stone column method is difficult to apply to the ground which is not mobilized enough lateral confine pressure because no bulging failure resistance. Hence, in present study, development the geogrid reinforced stone column system for settlement reduction and wide range of application of stone columns. To develop this system, triaxial compression tests were conducted for evaluation which is about behavior characteristics of stone column on replacement rate and confine pressure. Then, 3-dimensional numerical analysis were evaluated for application of the GRSC (geogrid reinforced stone column) system as evaluate behavior characteristics and settlement reduction effect of stone column reinforced by geogrid on types and reinforcing depth change of geogrid.